TY - JOUR
T1 - Effect of surface coating on the photocatalytic function of hybrid CdS-Au nanorods
AU - Ben-Shahar, Yuval
AU - Scotognella, Francesco
AU - Waiskopf, Nir
AU - Kriegel, Ilka
AU - Dal Conte, Stefano
AU - Cerullo, Giulio
AU - Banin, Uri
N1 - Publisher Copyright:
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA.
PY - 2015/1
Y1 - 2015/1
N2 - Hybrid semiconductor-metal nanoparticles are interesting materials for use as photocatalysts due to their tunable properties and chemical processibility. Their function in the evolution of hydrogen in photocatalytic water splitting is the subject of intense current investigation. Here, the effects of the surface coatings on the photocatalytic function are studied, with Au-tipped CdS nanorods as a model hybrid nanoparticle system. Kinetic measurements of the hydrogen evolution rate following photocatalytic water reduction are performed on similar nanoparticles but with different surface coatings, including various types of thiolated alkyl ligands and different polymer coatings. The apparent hydrogen evolution quantum yields are found to strongly depend on the surface coating. The lowest yields are observed for thiolated alkyl ligands. Intermediate values are obtained with L-glutathione and poly(styrene-co-maleic anhydride) polymer coatings. The highest efficiency is obtained for polyethylenimine (PEI) polymer coating. These pronounced differences in the photocatalytic effi ciencies are correlated with ultrafast transient absorption spectroscopy measurements, which show a faster bleach recovery for the PEI-coated hybrid nanoparticles, consistent with faster and more effi cient charge separation. These differences are primarily attributed to the effects of surface passivation by the different coatings affecting the surface trapping of charge carriers that compete with effective charge separation required for the photocatalysis. Further support of this assignment is provided from steady-state emission and time-resolved spectral measurements, performed on related strongly fluorescing CdSe/CdS nanorods. The control and understanding of the effect of the surface coating of the hybrid nanosystems on the photocatalytic processes is of importance for the potential application of hybrid nanoparticles as photocatalysts.
AB - Hybrid semiconductor-metal nanoparticles are interesting materials for use as photocatalysts due to their tunable properties and chemical processibility. Their function in the evolution of hydrogen in photocatalytic water splitting is the subject of intense current investigation. Here, the effects of the surface coatings on the photocatalytic function are studied, with Au-tipped CdS nanorods as a model hybrid nanoparticle system. Kinetic measurements of the hydrogen evolution rate following photocatalytic water reduction are performed on similar nanoparticles but with different surface coatings, including various types of thiolated alkyl ligands and different polymer coatings. The apparent hydrogen evolution quantum yields are found to strongly depend on the surface coating. The lowest yields are observed for thiolated alkyl ligands. Intermediate values are obtained with L-glutathione and poly(styrene-co-maleic anhydride) polymer coatings. The highest efficiency is obtained for polyethylenimine (PEI) polymer coating. These pronounced differences in the photocatalytic effi ciencies are correlated with ultrafast transient absorption spectroscopy measurements, which show a faster bleach recovery for the PEI-coated hybrid nanoparticles, consistent with faster and more effi cient charge separation. These differences are primarily attributed to the effects of surface passivation by the different coatings affecting the surface trapping of charge carriers that compete with effective charge separation required for the photocatalysis. Further support of this assignment is provided from steady-state emission and time-resolved spectral measurements, performed on related strongly fluorescing CdSe/CdS nanorods. The control and understanding of the effect of the surface coating of the hybrid nanosystems on the photocatalytic processes is of importance for the potential application of hybrid nanoparticles as photocatalysts.
KW - Charge transfer dynamics
KW - Hybrid nanoparticles
KW - Hydrogen evolution
KW - Photocatalysis
KW - Surface coatings
UR - http://www.scopus.com/inward/record.url?scp=85027958671&partnerID=8YFLogxK
U2 - 10.1002/smll.201402262
DO - 10.1002/smll.201402262
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:85027958671
SN - 1613-6810
VL - 11
SP - 462
EP - 471
JO - Small
JF - Small
IS - 4
ER -